<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>

<body>
    手机号码: <input type="number" name="" id=""><button>发送</button>
    <script>
       var btn = document.querySelector('button');
       var time = 10
       btn.addEventListener('click', function() {
           btn.disabled = true;
           var timer = setInterval(function() {
               if(time == 0) {
                   clearInterval(timer);
                   btn.disabled = false;
                   btn.innerHTML = '发送';
                   time = 10;
               }else{
                   btn.innerHTML = '还剩下' + time + '秒';
                   time--;
               }
           }, 1000);
       })
    </script>
</body>

</html>